Abstract
CO2 hydrate formation in pipelines for CO2 transport and storage can cause severe flow blockage, posing a major flow assurance challenge in CCUS infrastructure. To address this issue, three amino acid derivatives (sarcosine, N,N-dimethylglycine, creatine) were investigated as environmentally friendly CO2 hydrate inhibitors using complementary experimental and computational approaches. Onset temperature and gas uptake measurements showed that these amino acid derivatives effectively delayed CO2 hydrate nucleation and retarded hydrate growth, with creatine exhibiting inhibition performance comparable to that of the commercial kinetic hydrate inhibitor, polyvinylpyrrolidone (PVP). Molecular dynamics (MD) simulations were further employed to investigate how structural differences among amino acid derivatives influence water structure and the overall inhibition mechanism. The amino acid derivatives inhibited CO2 hydrate formation through strong interactions with surrounding water molecules, thereby perturbing the hydrogen-bond network and local water structure. The molecular structure of each derivative further influenced the organization of nearby water molecules, resulting in distinct hydration environments. These findings demonstrate the potential of amino acid derivatives as sustainable CO2 hydrate inhibitors and provide molecular-level guidance for designing environmentally friendly KHIs for CO2 transport and storage systems.